Synthesis & characterization of natural soil based inorganic polymer foam for thermal insulations

Thermal insulations are important in controlling the inner environment of the buildings. Geopolymer foams, also known as inorganic polymer foams, have attracted more attention among the inorganic class because of their sustainability and being environment friendly materials. In this research work natural soil based inorganic polymer foams have been successfully produced using low cost and abundantly available soil as aluminosilicate precursor. Samples with varying amounts of soil and liquid contents (NaOH and Na2SiO3 as alkaline activator solution) were used to prepare foams where hydrogen peroxide was used as foaming agent. The foamed slurries were poured into the molds and cured. The minimum thermal conductivity of 0.2670 W/mK was achieved at bulk density of 0.8630 gcm−3, total porosity of 63.1% and compressive strength of 2.41 MPa for inorganic polymer foam containing 70% soil and 30% liquid composition. The highest compressive strength was achieved at 74% soil and 26% liquid composition. These properties were related to degree of inorganic polymerization using XRD and FTIR analyses. These foam materials can potentially be used as building thermal insulations.